Eine indicator and automatic bottom margin warning mechanism for a typewriter



Oct. 29, 1957 Sl-LING Ts'Ao LINE INDICATOR AND AUTOMATIC BOTTOM MARGIN WARNING MECHANISM FOR A TYPEWRITER 2 Sheets-Sheet 1 Filed Aug. 24, 1956 ,R. a dillllllllllllll INVENTOR.

*EW ATTOZ 1V5 Y5 2 Sheets-Sheet 2 0 1957 SI-LING Ts'Ao LINE INDICATOR AND AUTOMATIC BOTTOM MARGIN WARNING MECHANISM FOR A TYPEWRITER Filed Aug. 24, 1956 United States Patent 6) This invention relates to typewriters, and more par-. ti'cularly to a line-indicator and automatic bottom margin warning-mechanism for a typewriter.

The main object of the inventi'onis to provide a novel and improvedlineindicating and bottom margin Warning; mechanism for a typewriter, said mechanism involving siinple= components, being relativelycompact: in size, and

being suitable for installation on a; typewriter" ofconventional construction.

A further object of' the invention is to-provide an'imiproved line indicator and bottom marg warning mech .anism for a typewriter, said mechanism involving inexpensive parts, being durable in construction, and provid.

ing' a continuous indicationof the number of lines ad vaneedon a sheet of paper in' a typewriter, as' well. as

providing an automatically operated audible warning whenjthe-last line to be written has beenreached:

A stillfurther object of the invention is to provide an improved line indicator andbottom-marginwarning;

mechanism for' a typewriter; said mechanism being easy to setupfor use, being automaticallyplaced inopera: tionresponsive tothe actuation of any of'the-letterkeys,

the-shift key or the space bar of the typewriter, as desired by thetypist, and beingarrangedso-thatitis autoinatical': lycleared for the initiation of a line; counting operation by the act of placing a sheet of paper-in the typewriter.

Further-objects and advantages ofthe invention will'become apparent from the following-description and claims;

and from the accompanying drawings, wherein:

Figure l is a fragmentary; top-plan view of the carriage portion ofa typewriterprovided with an improvedfline indicator and automatic bottommargin; warning mechanism constructed in accordance with the present inven- 'tion.

Figure 2 is a longitudinal vertical cross-sectional view taken on the line 22 of Figure 1-. a

Figure 3 is a transverse vertical cross sectional view taken on the'line 3--3-of Figure l.

Figure 4 is a vertical cross sectional: detail view taken- :on the line 44 of Figure 3.

Figure-5 is a transverse vertical cross sectional detail view'taken on the line 55 of Figure 1.

Figure 6 is a fragmentary vertical cross sectionalview;

taken substantially on the line 6 -6- of Figure 1- and showing the connection of the space bar'to'the associated portions of the automatic line indicator and warning mechanism of the present invention.

Figure 7 is a fragmentary rear elevationalvi'ew'of the mechanism taken on the line 77 of Figure 6;

Figure 8 is a horizontal cross sectional view=takenon theline 88 of Figure 7.

Figure 9 is a fragmentary transverse verticalcross-s'ectional view taken on the line 9-9- of'Figure- 7, and showing the connection of the shift keyofthe typewriter to the associated portions of the automatic line indicator and warning mechanism of the present invention".

Figure 10 is a vertical cross sectionaldetail view'taken on the line 1010'of Figure 8, showing atypewriter tale-- 2,811,238 Patented Qct, 29, 195] "ice 2; mentwhichis actuatedresponsive to the-operationofanyofthe letter'keys of the typewriter and which-is associated withthe automatic'line indicator andwarningmechanism offthepre'sentinvention illustrated inthe preceding'viewsj. Figure 11 is a verticalcross sectional detail view-taken substantialy. on-theline. 11'1-11 of Figure 1, and showing the warning bell and the associated, operating mechanism therefor,- forming' part of" the present invention. Figure 12 is' an enlarged itransverse vertical cross. sec tional detail view taken ontheline 12'-'12?of"Figure;;1".- Referring to the; drawings 20 generally designates a typewriter of generally conventional construction" pro; vided with the usual. movable carriage 21" on which" is; mountedthe cylindrical platen member 22; which may be; in the form of an elongated rubber roller. Associated with the roller 22' is the conventional paper: holding, m'ech'anismwhieh is provided with agrelease'levertiicafi rie'd at'the end'of an arm 23 pivoted adjacentthe right endof' the: roller 22;.as' viewed'in Figure 1 The lever 23is movable upwardly; and'forwardly, for releasin'gthe mechanism associated therewith for the purposeofi inserting-a sheet of paper-in" the typewriter, namely,.,around the roller 22; V a

Ri l lY secured to the-carriage 21 at the right end. thereof is a. rearwardly' extendingarm- 24,;the roller shaft; extendingthrough the forward portion. of said arm and? being provided thereon with the adjusting knob. '25; whereby the roller 22 may be manually rotated from; the right en'd thjereof, as viewed in Figure; l. A rearwardly' extending arm 26 is secured to the left endofthej carriage fora purpose presently to he. described.

The left end of the roller 22;, as. viewed in Figure; l, is provided" with a ratchet" wheel'27wl 1ich is engaged in a conventional. manner bythe pawl element associated with the line spaee1lever Z810 rotate roller 22 respona; sive" to the actuation of thelinev space lever 2. 8 by the; typistj as the typist reaches thejen'd'ofaline'and wishes to' start a new line. 7 As is well understood, the operatic)1i; of the lever 28 returns the carriage for starting the new line andalso rotates the roller-22 to provide .the required line spacing The line spacingi'sdetermined inaccgrdancewith, the setting of the conventional line. spacing; adjusting lever 29, which maybe. setv to. provide e ithe z single spacing, double spacing, or triple spacing," as d'eI- Figure 1', is.provided witha knob 33', and with arelatiyea.

1y large sprocket wheel 34 secured on the rolier' 'shaft adjacent said knob 33, as showninFigure 1. The; left end portion of the roller shaft is designated at 3'5 Figure 3-, and the sprocket wheel 34 is rigidly securedon the roller shaft 35 so as to rotate simultaneously therewith.

rollfer shaft 35 is an auxiliaryshaft 3 6 on which. in rotatr ably mounted a relatively .srnallfi spro cket wheel' 37'vyhjehf is nmen w h h spr k t. he Mieniwhiqh s. coupled, to. sprocket wheel 3'4; by a. sprocket ehain 3. .1.

Ri'gidly secured to thesprocket wheel '37 is a relatively portion 45' on is journaled a supporting rollerflf. Designated n45 is a flexible tape'which engages over-the Secured to the arm' 26. rearwardly Qf andlparallelftoi 3 roller 44 and which is secured at one end thereof to a spring-biased reel member 46 contained in a drum-like housing 47 rigidly secured in any suitable manner to the frame of carriage 21 subjacent the feed screw 41, as shown in Figure 4, the reel 46 being rotatably mounted on a stationary shaft 48 provided centrally in the housing 47 and containing a spiral spring 49. Asshown in Figmeans inner end of the spring 49 is secured to the shaft 48 and the outer end of said spring is secured to the'peripheral wall of reel 46. The tape 45 is secured to the periphery of the reel 46, whereby the spring 49 acts to wind up the tape on the reel 46 under the tension provided by the spiral spring 49. I

' Designated at 50 is a pointer element which is rigidly secured. inany suitable manner to the bracket 42 in a position parallel to the shaft element 43 but with its tip located. adjacent the edge of the tape 45, as shown in Figure 1. i

A The outer end of tape 45 is secured to the block member 51 slidably mounted on the feed screw 41, said block being formed with the horizontal bore 52 through which the feed screw 41 extends, as shown in Figure 12.

Designated at 53 is a plate member which is provided at its opposite ends with shaft elements 54 and 55, said shaft elements being pivotally supported in the respective arms 24 and 26, whereby the plate member 53-is pivoted for rotation on an axis parallel to the feed screw 41 and 4 is engageable with the depending lower portion 66 of leaf spring 63 to flex the leaf spring 63 forwardly, away from the edge of the leaf spring 60, responsive to the clockwise rotation of plate member 53, as viewed in Figure 12, whereby to release leaf spring 60 from its downwardly flexed condition.

It will be understood that the bore 62 in the block 51 is of sufficient size to provide ample clearance for the projection 61 to allow said projection to angle in the bore as the spring 60 is flexed.

Designated at 68 is a vertical plunger element which is slidably mounted in the forward portion of the block member 51, the plunger 68 being provided with an e11 larged top head 69 which is biased upwardly by a coiled spring 70 surrounding the upper portion of the plunger 68 and bearing between the top surface of the block 51 and the head 69. As shown in Figure 12, the lower end of plunger 68rests on the leaf spring 60 but is normally ineffective to cause downward flexure of said leaf spring;

Designated at 71 is a longitudinally extending bar member which is disposed parallel to the feed screw 41 and which is rotatably supported on the shaft members 7 54 and 55 by arcuate arms 72 and 73 provided on the is located rearwardly adjacent said feed screw, as shown in Figure 1-. The plate member 53 is provided with a widened top portion, such as the flange or head 54, on which is inscribed a line margin setting scale 56, comprising evenly spaced calibrations corresponding to the number of lines of typewritten material which may be placed on a single sheet of typewriting paper. The tape 45 is calibrated with a similar scale.

As shown, the plate member 53 extends substantially vertically and is formed with a longitudinal slot 57 which extends. for the major portion of its length, as shown in Figure :2. Arearwardly extending guide pin 58 is secured to the rear surface of the'block 51 and extends slidably through the guide slot 57, supporting the block 51 for longitudinalmovement parallel to the plate 53.

Secured to the rear marginal portion of the block 51, as'by a machine screw 59, is a generally horizontal leaf spring. 60v on which is rigidly secured an upstanding lug 61 whichextends loosely through a vertical bore 62 formed in the block 51 and communicating with the bore 52. The lug '61 is shaped to at times engage between adjacent threads of the screw 41, as shown in Figure 12, whereby the block 51 will be moved longitudinally responsive to-rotation of screw 41. Spring 60 biases .the lug 61 upwardly in the bore 62 towards its thread-interengaging position, as shown in Figure 12.

Designated at 63 is a depending leaf spring secured at its upper portion to the upper marginal portion of the front surface of block 51, as by a machine screw 64. The leaf spring 63 is provided with an intermediate, downwardly and forwardly offset portion 65 and a terminating vertical portion 66 which is parallel to but forwardly offset from'the upper portion of the leaf spring 63, as shown in Figure 12. a 7

As shown in Figure 12, thelower marginal portion of the vertical upper element of leaf spring 63 is engageable with the edge of the horizontal leaf spring 60 when the lug 61.is in thread-interengaging position, and under these conditions, the leaf spring 63 has no effect. However, if the leaf spring 60 is slightly depressed so that its free outeredge engages the inclined portion 65 of leaf spring 6.3, leaf spring 63 is effective to depress the free outer portion of leaf spring 60 and to hold the lug 61 in lowered position, disengaged from the feed screw 41. This will continue until the leaf spring 63 is flexed outwardly, which is accomplished, at times, by rotation ofthe plate member 53, as will be presently described, said plate member 53 being provided with a forwardly extending arm 67 which respective ends of the bar 71 and located inwardly adjacent the carriage arms 24 and 26.

The bar member 71 is located immediately above the head .69 of plunger 68 and is of suflicient weight to depress the plunger 68 and to flex leaf spring 60 downwardly. However, the bar 71 is normally supported in an elevated position by an arm 74 rigidly secured to the paper releasing lever 23, as shown in Figure 5, the arm 74 being in alignment with and underlying the end arm 72 of arm 71 and slidably engaging the bottom surface of arm 72. As will be apparent from Figure 5, when the lever element 23 is rnoved upwardly and forwardly, as is done when a sheet of paper is inserted in the typewriter, the arm 72 is released, allowing the bar 71 to move downwardly and to engage head.69.- This causes plunger 68 to depress the leaf spring 60 and to cause the free end of said leaf spring 60 to lockingly engage beneath the downwardly and forwardly inclined intermediate portion 65 of leaf spring 63,:whereby the lug 61 is held in a disengaged position with respect to the threads of feed screw 41. Thus, the block member 51' is automatically released from the threads of the feed screw'when the paper release lever element 23 is pulled forwardly, namely,- when a sheet of paper is inserted in the typewriter. When this occurs, the-spring 49 associated-with the tape 45 acts to move the block 51 toward the left end of the typewriter carriage.

shown in Figure 12, a spacing washer or other suitable spacing element, designated at 75, is provided between the leaf spring 60 and the bottom surface of block member 51, providing a clearance space between the leaf spring and said bottom surface. A similar spacing washer or analogous element 76 is provided between the upper portion of leaf spring 63and the front vertical surface of block member 51.

Designated generally at 77 is a stop member for'limiting the movement of the block member 51 toward the right, said stop member 77 comprising a shaft element 78 which is engageable through the slot 57 and which is provided with alocking wing nut 79a clampingly engageable against therear surface of plate member 53. The forward portion of the stop member 77 comprises a yoke having a relatively short top arm 79 and a substantially longer bottom arm 80 which projects forwardly a substantial distance from thefeed'screw 41 which is received between arms 79 and 80, as shown in Figure 5. Themember 77 is suitably shouldered at 81 so that said member may be rigidly secured inadjusted position along the plate 53 by tightening the wing nut 79a. r

' The'lower arm 80 is substantially in the same horizontal plane as the space between leaf spring 60 and the bottom surface of block member 51 and is substantially aligned therewith.v Formed on the, end portion of the lower arm film's astaperedtwedge member 82=which is directed towards? the tspacevbetween-thezbottom surface :of block memberT'51; and-deaf: spring; and which-is engageable in said space when; the block member reaches a position along: feed= screw; 41 closely adjacent the stop member 77; As will hewreadily apparent; when the wedge member 82 engages betweenileaf spring 60 and thebottom surface of: block member 51-, the; leaf spring 60: willv bedeflected downwardly -and, willengage with the inclined portion of ;leaf spring:63; whereby the force of the leaf spring 63' willexert ascamming. action on the free forward 'end of leafspring 6i) and deflectvsaid'leaf spring 60 further downwardly,- as-.well1 as retaining the leaf spring 60 in a downwardly flexed position; As above explained, this disengagesthetop; end portion.- of lug 61 from between the threads ofthe feed screw: 41; releasing the block member 51 and allowing the spiraltspringz49s associated withrthe tape 45 to return theiblock'mern'ber toWard-the-left end ,of'carriage 21.

The-top, of the'block member 51 isprovided with an abiltmentt, block element 84: underlying the head- 69 of plungef 68; and limiting thetdownward movenrentofsaid; plungerproduced-by the action of bar member; 71 thereagainstwhen said bar member is released, as by the depression lof; the-paperrelease lever element 23.

' Mounted on the left end portionof the carriage21 is a warningbellt; saidbell being secured on a transversely extendingshorizontal shaft element 86, as shown in Figure 1,:located adjacent to the arm 26 and beneaththe'bar 71. Azciapper arm87 is pivoted at 88 to the typewriter carriage ZEl' and-Jis' provided with theclapper element 89 at one end thereof; received'inside the bell 85 and biased against the innerperipheral wallsurface of the hell by a coiled spring? 90connectin'g the opposite end portion of clapper arm 87 to the carriage 21.

Asshown in Figure 11; the clapper arm 87 is provided atzthe end thereof opposite the clapper 89 with a laterally extending bracket element 92;having anobliquely'extendingaextensi'on 93 to theend of Whichis pivoted a triangular pawl element 94: whose tapered. endextendsiinto the'path Of movement'of the block member 51; One'end' of: the spring-9.0v is connected to the opposite end of the=pawl element 94,.as shown in Figure 11, biasingtthe pawl'element'counterclockwise into engagement with alug 95; pro;- vided on the bracket member extension 93; The spring 90 thusza'cts to bias the wider portion of the pawl 94=against theilug 95', as well as to bias the clapper bar 87 in'a clockwise direction, as viewed in Figure 1'1, namely,,to bias the striking portion 89 of the clapper against the inside surface of the bell 85. When the block member 51' is released byengagement with the wedge-like element 82 on stop member 77, as above described, the tape biasing'spring 49 returns the block member 51 toward the left end of the carriage, whereby the block member 51 engages the tapered end porti'on of the pawl element 94', rotating the'clapper ar'rr'r'8 7 counterclockwise, as viewed in Figure 11, until the block member 51 slips past the tapered end of the pawl member 94; whereupon spring 90 returns the clapper arm 87 clockwise, causing the striker element 89 to strike the bell 85 and provide an audible signal. The block member 51is' free tomove to the right, as viewed in Figure 11, without-producing any actuation-of the bell 85, since the pawl element 94 is yieldable in a clockwise direction, as viewed in Figure 11, Without causing any rotation of the clapper a-rm 87l Thus, an audible signal is providedeach time the block member 51 travels toward the left endof the carriage 21 subsequent to the release of said block member-by thewedge element 82 on stop member 77.

When the block member 51 is moved to its extreme left position, as viewed in Figure 1, by the action of spiral spring 49 on tape 45, subsequent to the disengagement of projection 61 from the threads of screw 41', the block member actuates the warning bell 85, as above described,

and th'eii co'mes to rest'at'a position wherein the pointer" eleriae'rit 50 shows zero on'tape 45, this position being established by the location of the left end of slot 57,. since said deft; end 0fEs10t .'57 acts-asya Y stop nieanssto limittfunther'leftward {movement of pin member 58rinsaidysloty asf viewedinFiguresl and 2; V p i I V The gear ratios betweensprocketwheel tandsprocket wheel 37, and gear 39 and pinion'gear 40.are such aszto. provide a complete revolution ofthe feedscrew 4-1f01? rotation of platen roller 22through an angleeorrespending;-v

' mine at any time the number of lines typedbyreadingthe tape 45 at the pointer50, makingith'e'properfdediletionfor' the, number of lines allowedat the top margin. The same: information will be provided'by observing the positionof the zero point oftape 45"Wit1'i respectto scale 561 As mentioned'above the dev-icelis cleared for use by the act of operating the paperrele'a'se lever'me'mber, 2 3i in inserting a sheet of paper in the typewriter; When'this" occurs the block member 51 is retracted to its starting; position by the action of'the'spring49, the blockmember. 51 being released, as above describedjbythe release'of" bar 71 and the action of said bar on the plunger 68," the plunger being depressed thereby, whereby projection 61 is disengaged from the. threads of, feed s'creW'4'1.

As will be readily apparent, underthese condition s;;the"

leafspring 60Sis retainedinits downwardly flexed posi tion by the engagement, of its forward edgewithlthe; inclined retaining portion 65 of 'leafsprin'g '63, lngorder to set the line indicator into operation, it; is necejssary to free the leaf spring 60'so thatitheproje'ction 61"rnay again ascend into engagement with the thread'slof feed" screw 41. This is accomplished by causingplatej5'3to rotate clockwise, as viewed; in Figurel'Z, responsive to the operation of one of the normal operating; elements of the typewriter, otherthan'the' paper relea'seleyerele ment 23; Any of the operating elements'of the typewriter may be employed as, the means'fbrjrotatingjthe" plate member 53 sufficiently to. causethe arm; 67. teen gagethe depending lower portion66 of"s'pring 63, As will be apparent from Figure. 12, when the end, of the arm' 67 engages spring portion 66, the member 6 3 is flexed outwardly, allowing'the spring 601toj returnit'o its normal position, shown inv Figure 12; whereinth'e top end of projection 61 is interengaged'with the, threads of feed screw 41. V

In the embodiment of the invention illustratedlin the drawings, means is provided whereby'the" operatormay select either the typewriting key elements, the space bar, or the shift key of the typewriter as themeans 'for'initiat'ing the operation of the line indicating and" bottom margini warning device.

Rigidly secured to the back wall of" the typewriter frame and projecting rearwardly' and. horizontally there' from are a pair of supporting arms 111,111., Rbt'atably mounted in the ends of the armslll, 11-1 and; extending parallel to the typewriter rear wall 100 is" a shaft 104 on: which is secured an arm 105' formed at it'stop endrwith' the'rearwardly offset stop member 8'3whi ch engages the plate member 53, as'shown i'nFigures 6 and Rigijcllysecured to the intermediateportion of shaft 104fis': an

upstanding arm 103'; Another upstanding iS;' rigidly secured to the end of shaft 1f04 oppositethe-"armr;

105 Rigidly secured to the top endsofthe arms 10 the respective horizontal, forwardly-extending-arm 02 10-2; 1 Slidablybut non -rotativelymountediir tlie f end-'' portions of the horihontaliarm's 162, 102 a a -n6 zontal rod member 101, extending parallel to the back wall 100 of the typewriter frame and located between said back wall and the rear rod 104, as shown in Figure 8. Secured rigidly on one end of the rod member 101 is a cylindrical block member 121 formed at its bottom with four evenly spaced transversely extending grooves 122, 123, 124 and 125. V

' Extending rotatably through the intermediate portions of the arms 111, 111 is a horizontally extending rod member 126 having an arm 110 rigidly secured to the intermediate portion thereof, said arm extending upwardly and being engageable in any one of the grooves 122, 123, 124, and 125, depending upon the longitudinally adjusted position of the rod 101. The arm 110 is biased to an upstanding position wherein its top end is engageable in one of the grooves 122, 123, 124 or 125 by a coiled spring 113 connecting arm 110 to a rearwardly adjacent upstanding arm 105 secured on shaft 104.

As' will be readily apparent, the arm 110 may be manually rotated to disengage its top end from the groove in the bottom of the member 121, whereby said member 121 may be shifted longitudinally by hand, if so desired.

Integrally formed with the longitudinally adjustable rod 101 are the forwardly divergent side arms 107, 107 which extend forwardly and horizontally and which are rigidly connected together by a horizontally extending bar member 106 disposed parallel to the rear wall 100 of the typewriter inside the typewriter housing. As

shown, the arms 107 extend through a slot 129 formed in the rear wall 100 of the typewriter frame.

Rod member 106 has an end extension 130 which may be at times engaged with the hook-like member 131 forming part of the conventional existing shift key mechanism, illustrated in Figure 9, wherein the typewriter shift key is shown at 132. As is illustrated in Figure 9, the shift key'mechanism terminates in an upstanding serrated element 134 and the bar member 106 is located on an axis just within the corner defined between the upstanding element 134 and the remainder 135 of the link member 131 on which memberl134 is formed. Thus, the end 1300f bar member 106 may be at times engaged in said corner by suitably adjusting the rod 101. Such engagement may be accomplished by setting rod member 101 so that the top end of arm 110 engages in the notch 122. Under these conditions, when the shift key 132 is depressed, the link member 135 is moved forwardly, as viewed in Figure 9, moving the bar member 106 forwardly, and thereby causing shaft 104 to be rotated counterclockwise, as viewed in Figure 6, which in turn causes stop arm 83 to act against the plate member 53 and rotate said plate member clockwise. The clockwise movement-of plate member 53 causes arm 67 to engage against the depending lower portion 66 of leaf spring 63, flexing the leaf Spring outwardly and releasing the leaf spring 60,.if said leaf spring 60 has become engaged with the inclined retaining portion 65 of leaf spring 63.

Thus, the device may be set so that the line indicating and bottom margin warning mechanism is set into operation responsive to the depression of shift key 132. This isv done by adjusting the rod member 101 manually so that the top end of arm 110 engages in the first groove 122.

Designated at 136 is a conventional element, already existing in the typewriter which is located Within the typewriter housing forwardly of the rear wall 109, as shown in Figure 6. Member 136 represents any one of a number of elements of the typewriter which rotate responsive to the depression of any of the letter keys of the typewriter.

Rigidly secured to the member 136 is a rearwardly extending arm 137 formed at its rear end with a depending lug 114, Secured on the bar member 106 is an upstanding pin 108 which is engageable by the lug 114 when the bar member is adjusted to the position thereof shown in Figures'7 and 8, namely, wherein thet-op endofarm 110 engages in the second transverse bottom groove 1 23 of member 121. As shown in Figure 6, the arm 137 is connected to the lower portion of the member 136, and

V the member 136 rotates clockwise,- as viewed in Figure 6, responsive to depression of any of the typewriter letter keys, whereby the rod 101 is moved forwardly, causing shaft 104 to rotate counterclockwise, as viewed in Figure 6. The stop member '83 acts against the plate member '53 to rotate said plate member clockwise, as viewed in Figure 6, and to cause arm 67 to flex leaf spring 63 outwardly, releasing leaf spring 60, and initiating the operation of the line indicating and bottom margin warning mechanism.

Rigidly secured to bar member 106 is 3. depending lug 138, located opposite the upstanding lug 108, the depending lug 138 being at times engageable by an upstanding lug formed on the end of the link member 139- connected to the space bar mechanism of the typewriter and arranged to move forwardly responsive to the depression of the space bar, as shown at 140. As shown in Figure 8, the link member 139 is laterally spaced from the member 137 by a distance equal to the spacing between the bottom groove 123 and the bottom groove of member 121. Thus, by adjusting the rod 101 to a position wherein the top end of arm 110 engages in bottom groove 125, the lug 138 is placed in a position to be engaged by the upstanding lug 115 on space bar link member 139 when the space bar 140 is depressed. Under these conditions, the depression of the space bar will rotate stop member 83 counterclockwise and will rotate plate member 53 clockwise, as viewed in Figure 6, releasing the leaf spring 60 in the manner above described, and initiating the operation of the line indicating and bottom margin Warning mechanism.

When the top end of the arm 110 is engaged in the groove 124, the line indicating and bottom margin warning mechanism will not be operated.

From the above description, it will be readily apparent that the device is automatically cleared for action when the paper release lever member 23 is moved forwardly in inserting a sheet of paper in the typewriter. After the typist sets the paper in the machine at the proper position with the desired top margin, he begins to type. In accordance with the setting of the rod 101,

as above described, the actuation of either any one of the letter keys, the shift key, or the space bar will set the line indicating and bottom margin warning device.

into operation. From this point on, the advancement of the paper, line by line, will move the block member 51 to the right, step by step, until 'the desired number of lines are completed. If the roller 22 is then rotated one further step of rotation, the wedge element 82 on stop member 77 engages between block member 51 and leaf spring 60, flexing the leaf spring downwardly and releasing the block member. The tape 45 is then wound up by the spiral spring 49, moving the block member 51 to the left, as viewed in Figure 1, and actuating the bell 85. This provides a warning that the bottom margin of the sheet has been reached. The sheet may then be removed, and a new sheet may be inserted, which clears the device, if necessary, for the next cycle of operation.

While a specific embodiment of an improved line indicating and bottom margin warning device for typewriters has been disclosed in the foregoing description, it will be understood that various modifications within the spirit of the invention may occur to those skilled in the art. Therefore, it is intended that no limitations be placed on the invention except as defined by the scope of the appended claims.

What is claimed is:

1. In a line indicating and bottom margin warning device for typewriters, a typewriter carriage, a platen roller journaled on said carriage, a feed screw journaled on said carriage parallel to said roller, a block member ;slidably mounted on said screw, a movable couplingelo ment on said block member normally engaged with the: threads of said screw, reel means secured to said car 'riage, a flexible tape having line indicating; markings thereon secured at one end to said reel means andatthe other end to said block member, means supporting said tape on said carriage parallel to said feed screw, spring means urging said reel means to wind up said tape thereon, means drivingly coupling said feed screw to said platen roller and being formedand arranged to rotate said screw responsive to rotation ofsaid platen roller, and guide means on the carriage extending parallel to the screw, said guide means being formed and arranged to coact with said block. member to guide the riage, a flexible tape having line indicating: markings thereon secured at one end to said reel means and at the other end to said block member, means supporting said tape on said carriage parallel tosaid feed screw, spring means urging said reel means to wind up said tape thereon, means drivingly coupling said: feed screw to said platen roller and being formed and arranged to rotate said screw responsive to rotation of said platen roller, guide means on the carriage extending parallel to the screw, and a projection on said 'block member slid ably engaged with said guide means, said guide means being formed :and arranged to coact with said projection to guide the block member longitudinally on the screw and to prevent rotation of said block member on said screw.

3. In a line indicating and bottom margin warning device for typewriters, a typewriter carriage, a platen roller journaled on said carriage, :a feed screw'journaled on said carriage parallel to said roller, a block member slidably mounted on said screw, a movable'coupling element on said block member normally engaged with the threads of said screw, reel means secured to said carriage, a flexible tape having line indicating markings'thereon secured at one end to said reel means and. at the other end to said block member, means supporting said tape on said carriage parallel to said feed screw, spring means urging said reel means to wind up said tape thereon, means drivingly coupling said feed screw to said platen roller and being formed and arranged to rotate said screw responsive to rotation of said platen roller, guide means on the carriage extending parallel to the screw, said guide means being formed and arranged to coact with said block member to guide the block member longitudinally on the screw and to prevent rotation of said block member on said screw, a stop member adjustably' secured on said carirage in the path of movement'of' said block member, and cooperating means on theblock member and stop member formed and arranged to disengage said coupling element from the threads of the feed screw responsive to movement of the block member to a position adjacent said stop member.

4. In a line indicating and bottom margin warning device for typewriters, a typewriter carriage,a platen roller journaled on said carriage, a feed screw journaled on said carriage parallel to said roller, a block member slidably mounted on said screw, a movable coupling elemeans drivingly coupling-j said feed screw to said. platen? roller and being formed and arranged to: rotate: said screw responsive to rotation of said: platen roller, guide? means on the carriage extending parallel to the screw;-. said guide means being formed and arranged to coact' with said block member to guide thebloclc member 1ongitudinally on the screw and to prevent rotationof said block member on said screw, a stop member adjustabl y mounted on-saidcarriage in the path of movement of said block member, cooperating means on the blocle member and stop member formed and arrangedto dis? engage said coupling element from the threads ofthefeed screw responsive to movement of the block member to a position adjacentthe stop member, a. sounder on:

the carriage adjacent the path: of movementof the blocle' member, and actuating means on the sounder formedand' arranged to operate said sounder responsive to movement of the block member therepast in one direction but not in the other direction.

5. Ina line indicating and bottom margin warningfde vice for typewriters, atypewritercarriage, aplaten roller journaled on said carriage, a feed screw journaled onsaid carriage parallel to said roller, a' blockmember slidably mounted on said screw, amovable coupling ele-- ment on said block member normally engaged with themeans drivingly coupling said feed screw to said platen" roller and being formed and: arranged to rotate said screw responsive to rotation of said platen. roller, a plate: member mounted on said carriage parallel to said feedscrew, said'plate member being formed with a slot ex tending parallel to said feed screw, and a projection on. said block member slidably engaged in said slot to guide said'block member longitudinally on the screw, and to, prevent rotation of said block member on said screw;

6. ha line indicating and bottom margin warning, de=' vice for typewriters, a-typewriter carriage, a platen-roller journaled on said carriage, a feed screw journaled 011* said carriage prallel to said roller, a block member slidably mounted on said screw, a movable coupling el'eme'nton said block member normally engaged with the threadsof said screw,'reel means secured to said carriage,- a

flexible tape having line indicating markings thereon: seicured at one end to said reel means and at-the other end to said block member, means supportingsaid' tapeo'n said carriage parallel to said feed screw, spring means:

urging said reel means to wind up said tape thereon; means drivingly coupling said feed screw to said platen rollerand being formed and arranged to' rotate said screw responsive to rotation of said platen roller, a-plate mem bermounted on said carriage parallel to said 'feed screw, said plate member being formed with a slot' extending parallel to said feed screw, a projection on said block member slidably engaged insaid slot to guide said block member longitudinally on the screw and to prevent ro-" 1 member formed and arranged: to disengage said couplingelement from the threads of said screw responsive to movement of theblock. member toa position adjacent the stop member.

7. In a line indicating and bottom margin warning device for typewriters, a typewriter carriage, a platen roller journaled on said carriage,- a feed screwjo'urnaled on said feed screw, reel means secured to said carriage, a flexible tape having line indicating markings thereon secured at one end to said reel means and at the other end to said block member, means supporting said tape on said carriage parallel to said feed screw, spring means urging said reel means to wind up said tape thereon, means drivingly coupling said feed screw to said platen roller and being formed and arranged to rotate said screw responsive to rotation of said platen roller, a plate member mounted on said carriage parallel to said feed screw, said plate member being formed with a slot extending parallel to said feed screw, a projection on said block member slidably engaged in said slot to guide said block member longitudinally on the screw and to prevent rotation of said block member on said screw, a stop member adjustably mounted on said plate member and extending in the path of movement of said block member, cooperating means on the block member and stop member formed and arranged to disengage said coupling element from the threads of said screw responsive to movement of the block member to a position adjacent the stop member, a sounder on the carriage adjacent the path of movement of the block member, and actuating means on the sounder formed and arranged to operate the sounder responsive to movement of the block member therepast in one direction but not in the other direction.

8. In a line indicating and bottom margin warning device for typewriters, a typewriter carriage, a platen roller journaled on said carriage, paper release means on the carriage operatively associated with said roller for releasing the paper with respect to the roller suflicient- 1y to insert a sheet of paper around the roller, a feed screw journaled on said carriage parallel to said roller, 2. block member slidably mounted on said screw, a movable coupling element on said block member engaged with the threads of said screw, a clearing element movably mounted on the block member and being engageable with the coupling element so as to disengage same from the screw threads responsive to movement of the clearing element, a bar member pivoted to the carriage parallel to the screw and overlying the clearing element, an element on said paper release means normally supporting said bar member and disengaging therefrom responsive to the movement of said paper release means to releasing position, reel means secured to said carriage, a flexible tape having line indicating markings thereon secured at one end to said reel means and at the other end to said block member, means supporting said tape on said carriage parallel to said feed screw, means urging said reel means to wind up the tape thereon, means drivingly coupling said feed screw to said platen roller, and guide means on the carriage formed and arranged to guide said block member longitudinally on said screw.

9. In a line indicating and bottom margin warning device for typewriters, a typewriter carriage, a platen roller journaled on said carriage, paper release means on the carriage operatively associated with said roller for releasing the paper with respect to the roller sufliciently to insert a sheet of paper around the roller, a feed screw journaled on said carriage parallel to said roller, a block member slidably mounted on said screw, a movable coupling element on said block member engaged with the threads of said screw, a clearing element movably mounted on the block member and being engageable with the coupling element so as to disengage same from the screw threads responsive to movement of the clearing element, a bar member pivoted to the carriage parallel to the screw and overlying the clearing element, an element on said paper release means normally supporting said bar member and disengaging therefrom responsive to the movement of said paper release means to releasing position, reel means secured to said carriage, a flexible tape having line indicating markings thereon secured at one end to said reel means and at the other end to said block member, means supporting said tape on said carriage parallel to said feed screw, means urging said reel means to wind 12 up the tapethereon, means drivingly coupling said feed screw to said platen roller, guide means on the carriage formed and arranged to guide said block member longitudinally on said screw, a stop member adjustably mounted'on' said carriage in the path of movementof said block member, and cooperating means on the block memberand stop member formed and arranged to disengage said coupling element from the screw threads responsive to movement of the block member to a position adjacent said stop member.

It). in a line indicating and bottom margin warning devicefor typewriters, a typewriter carriage, a platen roller journaled on said carriage, paper release means on the carriage operatively associated with said roller for releasing the paper with respect to the roller sufficiently to insert a sheet of paper around the roller, a feed screw journaled on said carriage parallel to said'roller, a block member slidably mounted on said screw, a movable coupling element on said block member'engaged with the threads of said screw, a clearing element movably mounted on the block member and being engageable with the coupling element so as to disengage same from the screw threads responsive to movement of the clearing element, a bar member pivoted to the carriage parallel to the screw and overlying the clearing element, an elementon said paper release means normally supporting said bar member and disengaging therefrom responsive to the movement of said paper release means to releasing position, reel means secured to said carriage, a flexible tape having line indicating markings thereon secured at one end to said reel means and at the' other end to said block member, means supporting said tape on said carriage parallel to said feed screw, means urging said reel means to wind up the tape thereon, means drivingly coupling said feed screw to said platen roller, guide means on the carriage formed and arranged to guide said block member longitudinally'on said screw, a stop member adjustably mounted on said carriage in the path of movement of said block member, cooperating means on the block member and stop member formed and arranged to disengage said coupling element from the screw threads responsive to movement of the block member to a position adjacent said stop member, .21 sounder on the carriage adjacent the path of movement of the block member, and actuating means on the sounder formed and arranged to operate the sounder responsive to movement of the block member therepast when the coupling element is disengaged from the screw threads. t

ll. In 'ailine indicating and bottom margin warning device for typewriters, a typewriter carriage, a platen roller journaled on said carriage, paper release means on the carriage operatively associated with said roller for releasing the paper with respect to the roller sufliciently to insert a sheet of paper around the roller, a feed screw journaled on said carriage parallel to said roller, a block member slidably mounted on said screw, a movable coupling element on said block member engaged with the threads of said screw, a clearing element movably mount- .ed'on the block member and being engageable with the coupling element so as to disengage same from the screw threads responsive to movement of the clearing element, a bar member pivoted to the carriage parallel to the screw and overlying the clearing element, an ele- 'ment on said paper release means normally supporting said bar member and disengaging therefrom responsive to the movement of said paper release means to releasing positiom'reel means secured to said carriage, a flexible tape having line indicating markings thereon secured at one end to said reel means and at the other end to said block member, means supporting said tape on said carriage parallel to said feed screw, means urging said reel means to wind up the tape thereon, means drivingly coupling said feed screw to said platen roller, guide means on the carriage formed and-arranged to guide said block member longitudinally on said screw, a plate member pivoted to said carriage parallel to saidfeed screw, resilient detent means formed and arranged to retain said coupling element in thread-disengaging position subsequent to the engagement of said clearing element with said coupling element, means on the plate member engageable with said detent means to release the coupling element responsive to rotation of the plate member, and means formed and arranged to rotate said plate member responsive to the operation of one of the operating elements of the typewriter other than the paper release means.

12. In a line indicating and bottom margin warning device for typewriters, a typewriter carriage, a platen roller journaled on said carriage, paper release means on the carriage operatively associated with said roller for releasing the paper with respect to the roller sufficiently to insert a sheet of paper around the roller, a feed screw journaled on said carriage parallel to said roller, a block member slidably mounted on said screw, a movable coupling element on said block member engaged with the threads of said screw, a clearing element movably mounted on said block member and being engageable with the coupling element so as to disengage same from the screw threads responsive to movement of the clearing element, a bar member pivoted to the carriage parallel to the screw and overlying the clearing element, an element on said paper release means normally supporting said bar member and disengaging therefrom responsive to the movement of said paper release means to releas ing position, reel means secured to said carriage, a flexible tape having line indicating markings thereon secured at one end to said reel means and at the other end to said block member, means supporting said tape on said carriage parallel to said feed screwpmeans urg ing said reel means to wind up the tape thereon, means drivingly coupling said feed screw to said platen roller, guide means on the carriage formed and arranged to guide said block member longitudinally on said screw, a plate member pivoted to said carriage parallel to said feed screw, resilient detent means formed and arranged to retain said coupling element in thread-disengaging position subsequent to the engagement of said clearing element with said coupling element, means on the plate member engageable with said detent means to release the coupling element responsive to rotation of the on said carriage in the path of movement of said block' member, and cooperating means on the block member and stop member formed and arranged to. disengage: said coupling element from the screw threads responsive to' movement of the block member to a said stop member.

13. In a line indicating and" bottom margin warning device fortypewriters, a typewriter carriage, a. platen roller journaled on said carriage, paper release means on the carriage operatively associated with said roller for releasing the paper with respect to the roller 'sufliciently to insert a sheet of paper around the roller, a feed screw journal'e'd on said carriageparallel to said roller; a block member slidably mounted on said screw, a movable coupling element on saidv block member engaged with the threads of said screw, a clearing element movably mounted on the block member and being engageable with the coupling. element so asto disengage same from the screw threads responsive to movement of the clearing element, a bait member pivoted to the carriage parallel to the screw and overlying the clearing. element, an element on said paper release means normally supporting said bar member anddisengaging therefrom responsive to the position adjacent movement of said paper release means to releasing position, reel means secured tosaid carriage, a flexible tape- 14 having line indicating markings thereon secured atone end to said reel means and at the other endito said block member, means supporting said tape on said rearriage parallel to said feed screw, means urging said reel means to wind up the tape thereon, means drivingly coupling said feedscrew to said platen roller, guide meansv on the carriage formed and arranged to guide said block member longitudinally on said screw, a plate member pivoted to said carriage parallel to said feed screw, resilient detent means formed and arranged to retain said coupling element in thread-disengaging position subsequent to the engagement of said clearing element with said coupling element, means onthe plate member engageable with said detent means to release the coupling element responsive to rotation of the plate member, means formed and arranged to rotate said plate memberresponsive to the operation of one of the operating elements of the typewriter, other than the paper release means, a sounder on the carriage adjacent the path of.

movement of said block member, and actuating means on the sounder formed and arranged to operate the sounder responsive to movement of the block member therepast when the coupling element is disengaged from the screw threads.

14. In a line indicating and bottom margin warning device for typewriters, a typewriter carriage, a platen roller journaled on said carriage, paper release means on the carriage operatively associated with said roller for releasingv the paper with respect to the roller sufficiently to insert. a sheet of paper around the roller, typewriting key elements, a feed screw journaled on said carriage parallel to said roller, a block member slidably mounted on said screw, amovable coupling element on said block member engaged with the threads of said screw, a clearing element movably mounted on the block member and being engageable with the coupling element so as to disengage same from the screw threads responsive to movement of the clearing element, a bar member pivoted to the carriage parallel to the screw and overlying the clearing element, an element on said paper release means normally supporting said bar member and disengaging therefrom responsive to the movement of" said paper release means to releasing position, reel meanssecured to said carriage, a flexible tape having line indicating markings thereon secured at one end to said reel means and at the other end to said blockmember, meanssupporting said tape on said carriage parallel to said feed screw, means urging said reel means to wind up said tape thereon, meansdrivingly coupling said feed screw to said platen roller, guide means on the carriage formed and arranged to guide said block member lon'gi-' tudinally on said screw, a plate member pivoted to said of the block member therepast when the coupling ele' ment is disengaged from the screw threads, a stop mem-- ber adjustably mounted on said carriage in the path of movement of said block member, cooperating means on 4 the block member and stop member formed and arranged to disengage said coupling element from the screw threads responsive to movement of the block member to a position adjacent said stop member, and means formed and arranged to rotate said plate member responsive tojthe operation of one of said key elements.

15. In a line indicating and bottom margin warning device for typewriters, a typewriter carriage, a platen roller journaled onsaid carriage, paper release means on the carriage operatively associated with said roller for releasing the paper with respect to the roller sufiiciently to insert a sheet of paper around the roller, a spacer bar, a feed screw journaled on said carriage parallel to said roller, a block member slidably mounted on said screw, a movable coupling element on said block member engaged with the threads of said screw, a clearing element movably mounted on the block member and being engageable with the coupling element so as to disengage same from the screw threads responsive tomovement of the clearing element, a bar member pivoted to the carriage parallel to the screw and overlying the clearing element, an element on said paper release means normally supporting said bar member and disengaging therefrom responsive to the movement of said paper release means to releasing position, reel means secured to said carriage, a flexible tape having line indicating markings thereon secured at one end to said reel means and at the other end to said block member, means supporting said tape on said carriage parallel to said feed screw, means urging said reel means to wind up the tape thereon, means driving coupling said feed screw to said platen roller, guide means on the carriage formed and arranged to guide said block member longitudinally on said screw, 21 plate member pivoted to said carriage parallel to said feed screw, resilient detent means formed and arranged to retain said coupling element in thread-disengaging position subsequent to the engagement of said clearing element with said coupling element, means on the plate member engageable with said detent means to release the coupling element responsive to rotation of the plate member, a sounder on the carriage adjacent the path of movement of said block member, actuating means on the sounder formed and arranged to operate the sounder responsive to movement of the block member therepast when the coupling element is disengaged from the screw threads, a stop member adjustably mounted on said carriage in the path of movement of said block member, cooperating means on the block member and stop member formed and arranged to disengage said coupling element from the screw threads responsive to movement of the block member to a position adjacent said stop member, and means formed and arranged to rotate said plate member responsive to the operation of said spacer bar.

16. In a line indicating and bottom margin warning device tor typewriters, a typewriter carriage, a platen roller journaled on said carriage, paper release means on the carriage operatively associated with said roller for releasing the paper with respect to the roller sufiiciently to insert a sheet of paper around the roller, a shift key member, a feed screw journaled on said carriage parallel to said roller, a block member slidably mounted on said screw, a movable coupling element on said block member engaged with the threads of said screw, a clearing element movably mounted on the block member and being engageable with the coupling element so as to disengage same from the screw threads responsive to movement of the clearing element, a bar member pivoted to the carriage parallel to the screw and overlying the clearing element, an element on said paper release means normally supporting said bar member and disengaging therefrom responsive tothe movement of said paper release means to releasing position, reel means secured to said carriage, a flexible tape having line indicating markings thereon secured at one end to said reel means and at the other end to said block member, means supporting said tape on said carriage parallel to said feed screw, means urging said reel means to wind up the tape thereon, means drivingly coupling said feed screw to said platen roller, guide means on the carriage formed and arranged to guide said block member longitudinally on said screw, a plate member pivoted to said carriage parallel to said feed screw, resilient detent means formed and arranged to retain said coupling element in thread-disengaging position subsequentto the engagement of said clearing element with said coupling said detent means to release the coupling element responsive to rotation of the plate member, a sounder on the carriage adjacent the path of movement of said block member, actuating means on the sounder formed and arranged to operate the sounder responsive to movement of the block member therepast when the coupling element is disengaged from the screw threads, a stop member adjustably mounted on said carriage in the path of movement of said block member, cooperating means on the block member and stop member formed and arranged to disengage said coupling element from the screw threads responsive to movement of the block member to a position adjacent said stop member, and means formed and arranged to rotate said plate member responsive to the operation of said shift key member.

17. In a line indicating and bottom margin warning device for typewriters, a typewriter carriage, a platen roller journaled on said carriage, feed means journaled on said carriage, a block member slidably mounted on said feed means, reel means secured to said carriage, a flexible line indicating tape secured at one end to said reel means and at the other end to said block member, means supporting said tape on said carriage, means urging said reel means to wind up the tape thereon, means drivingly coupling said feed means to said platen roller and being formed and arranged to operate said feed means responsive to the rotation of said platen roller, indicating means on said tape, and means to move said block member and said tape forwardly on the feed means responsive to the rotation of said platen roller.

18. In a line indicating and bottom margin warning device for typewriters, a typewriter carriage, a platen roller journaled on said carriage, feed means journaled on said carriage, a block member slidably mounted on said feed means, reel means secured to said carriage, a flexible line indicating tape secured at one end to the reel means and at the other end to said block member, means supporting said tape on said carriage, means urging said reel means to wind up the tape thereon, means drivingly coupling said feed means to said platen roller and being formed and arranged-to operatesaid feed means responsive 'to the rotation of said platen roller, indicating means on said tape, means to move said block member and said tape forwardly on the feed means responsive to the rotation of said platen roller, a stop member adjustably secured on said carriage in the path of movement of said block member, and means whereby said block member and said stop member coact when said block member reaches a position adjacent said stop member to release said block member and allow said block member to be moved back by said reel means to its starting position.

19. In a line indicating and bottom margin warning device for typewriters, a typewriter carriage, a platen roller journaled on said carriage, feed means journaled on said carriage, a block member slidably mounted on said feed means, reel means secured to said carriage, a flexible line indicating tape secured at one end tosaid reel means and at the other end to said block member, means supporting said tape on said carriage, means urging said reel means to wind up the tape thereon, means drivingly coupling said feed means to said platen roller and being formed and arranged to operate said feed means responsive to the rotation of said platen roller, indicating means on said tape, means to move said block member and said tape forwardly on the feed means responsive to the rotation of said platen roller, a stop member adjustably secured on said carriage in the path of movement of said block member, means whereby the block member and said stop member coact when said block member reaches a position adjacent said stop member to release said block member and allow said block member to be pulled back by said reel means to its starting position, a sounder on the carriage adjacent the path of movement of said block member, and actuating means on the sounder ,formed and arranged to operate said sounder responsive to movement of said block member therepast in one direction but not in the other direction.

20. In combination with the structure of claim 19, paper releasing means on the carriage operatively associated with said roller for releasing the paper with respect to the roller sutliciently to insert a sheet of paper around the roller, and a clearing mechanism operated by said releasing means formed and arranged to allow said block member to be pulled back by said reel means responsive to the operation of said paper releasing means.

21. In combination With the structure of claim 20, a shift key, and means formed and arranged to initiate the advance of said block member on said feed means responsive to the operation of said shift key.

18 22. In combination with the structure of claim 20, letter keying elements and means formed and arranged to initiate the advance of said block member on said feed means responsive to the operation of any of said keying elements.

23. In combination with the structure of claim 20, a space bar, and means formed and arranged to initiate the advance of the block member on said feed means responsive to the operation of said space bar.

References Cited in the file of this patent UNITED STATES PATENTS 2,459,885 Krogseng J an. 25, 1949 

